1. Field of the Invention
The present invention relates in general to a shift control mechanism of an automotive manual transmission, and particularly to a shift control mechanism of a transversely mounted manual transmission which is particularly adaptable for use in a F.F (front engine front drive) type automotive vehicle having a transversely mounted engine.
2. Description of the Prior Art
In the transmissions of the type mentioned above, the shift control mechanism is usually so arranged that a control rod actuated by the manual shift lever in the vehicle cabin extends perpendicular to the axis of the fork shaft on and along which shift forks slide. Thus, a so-called "direction changing mechanism" is arranged between the control rod and the shift forks, which functions to convert the axial movement of the control rod to a sliding movement of selected one of the shift forks along the fork shaft. One of the direction changing mechanisms is disclosed in Japanese Patent Application First Publication No. 57-139830 which was laid open Aug. 30, 1982. The mechanism disclosed comprises generally a plurality of L-shaped pivoting levers which are pivotally mounted on a common pin secured to the housing of the transmission, one end of each pivoting lever being articulated with an extension of the corresponding shift fork and the other end of the same being formed with a rectangular recess into which a head portion of a shift arm secured to the control rod is selectively insertable to form an articulated connection therebetween. Upon selecting operation of the manual shift lever, the head portion of the shift arm is rotated together with the control rod travelling the path defined by the aligned recesses of the pivoting levers and stops in one of the recesses, and upon shifting operation of the manual shift lever after the selecting operation, the head portion of the shift arm is moved axially together with the control rod thereby pivoting the selected pivoting lever. With this, the associated shift fork is moved to a certain coupling position thereby to establish a certain gear ratio.
In the known direction changing mechanisms of the type mentioned above, however, the selecting movement of the head portion of the shift arm in the path of the aligned recesses and the shifting movement of the head portion in the selected recess have sometimes caused troublesome or uncomfortable manipulation of the manual shift lever by the operator (driver). Some of the known direction changing mechanisms will be briefly described in the last paragraph of the specification with their undesirable phenomena. Inventors have revealed that these undesirable phenomena originate from the inherent construction of the head portion of the shift arm and that of the recess of each pivoting lever.